The research will study behavioral factors that influence barbiturate and nonbarbiturate sedative abuse. The research will be cconducted in a controlled hospital setting using volunteer human subjects with an established history of sedative abuse. The aim of the research is to develop new behavioral methods for the treatment of sedative abuse. The research will employ human drug self-administration techniques to compare: 1) reinforcing properties of representative sedative compounds; 2) behavior-elimination procedures for reducing sedative intake; and 3) reinforcement procedures for establishing alternative non-drug behavior. The optimum combination of procedures will be applied in a treatment program for the research subjects, with later follow-up evaluation.